I posted a while back that my Icom 735 would have trouble only on 20M with RF back in to the radio. This would happen barefoot on the mobile with a hamstick or with the same radio as a base via an inverted V. This antenna is about 20 yards from the shack but here the radio barefoot was fine but still had the problem as when mobile but only when the amp was used. (SB200) I had wanted to get a desk mic anyway and thought it might be the culprit with the RF problem on 20M. I settled on the Heil iCM as it is designed for older Icoms. Well, the problem is gone and the audio is nicer as well. A decent mic for a decent price too hardwired (no XLR) with the 8 pin plug ready for the Icom.